Directional bend sensing with a CO2-Laser-Inscribed long period grating in a photonic crystal fiber

Long Jin, Wei Jin, Jian Ju

Research output: Journal article publicationJournal articleAcademic researchpeer-review

50 Citations (Scopus)


In this paper, we present a directional bend sensor based on a long period grating (LPG) formed by introducing periodic grooves along one side of a photonic crystal fiber (PCF) with a focused CO2laser beam. A bend sensitivity of 2.26 nm/m-1within a range of -5 ∼ +5 m-1is experimentally demonstrated. Numerical simulation suggests that the directional response is the result of asymmetric cladding geometry resulted from collapse and/or deformation of air holes and asymmetric material-index modulation caused by one-sided illumination of the CO2laser beam. The sensitivity could be further enhanced by increasing the area of the air-silica photonic crystal cladding and optimizing the size of individual air holes. The easy fabrication process and good linear response of the proposed sensor make it a suitable candidate for structural shape sensing in harsh environments.
Original languageEnglish
Pages (from-to)4884-4891
Number of pages8
JournalJournal of Lightwave Technology
Issue number21
Publication statusPublished - 1 Nov 2009


  • Directional bend sensing
  • Long period grating (LPG)
  • Optical fiber sensor
  • Photonic crystal fiber (PCF)

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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